Embodiments described herein relate to methods and systems for interrupted counting of items in containers.
Representing a numerical value by a countable collection of items is a well-known method for information storage, and has been implemented in devices, such as abacuses and ballot boxes, since calculations were performed in ancient times. In the case of the abacus, a number is represented by beads on a bar. When more than one numerical value has to be stored at the same time, the straightforward method is to use multiple containers, and in the case of the abacus, multiple bars of beads.
The stored number of items in a container can be read in several ways, including:                (1) (a) looking into the container; and                    (b) visually counting the number of items;                        (2) (a) pouring the items out of the container so that the items are easily exposed for counting;                    (b) segmenting the area in which the items are located;            (c) counting the number of items in each segment; and            (d) summing the count of items in each segment to arrive at the total number of items; and                        (3) (a) weighing the container with the items;                    (b) subtracting the weight of the empty container; and            (c) dividing the total item weight by the weight of a single item.                        
When accurate counting is required, and the items are not visible from outside the container, a practical method for counting is to sequentially extract the items from the container, ensuring that each extraction corresponds to exactly one object, and counting the extractions. Such a method is used in situations that require counting accuracy (e.g., for counting envelopes in a ballot box).
Such a method of counting by extraction is useful when there is a single container. However, when there is a plurality of containers containing the same type of items, such a method is very sensitive to interruptions. An interruption, such as a sudden gust of wind that could move everything that is not secured within the container, could cause the counting agent (i.e., the person counting the items) to lose count of the items.
When a large number of containers are being counted simultaneously (i.e., one item is extracted from every container in each cycle of counting until all the containers are empty) an interruption could interfere with and ruin the count. There are many cases in which large numbers of containers have to be counted mechanically and simultaneously, and therefore the conventional counting methods, which are not immune to interruptions that disrupt the count of unprotected items, are problematic. An example for such interruption is a sudden loss of power in a counting system that stores the number of successful extractions in a volatile memory.
It would be desirable to have methods and systems for interruptible counting of items in a plurality of containers.